全文获取类型
收费全文 | 269篇 |
免费 | 7篇 |
专业分类
林业 | 14篇 |
农学 | 7篇 |
基础科学 | 1篇 |
66篇 | |
综合类 | 10篇 |
农作物 | 17篇 |
水产渔业 | 39篇 |
畜牧兽医 | 82篇 |
园艺 | 1篇 |
植物保护 | 39篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 9篇 |
2020年 | 7篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 16篇 |
2014年 | 9篇 |
2013年 | 23篇 |
2012年 | 13篇 |
2011年 | 15篇 |
2010年 | 14篇 |
2009年 | 12篇 |
2008年 | 22篇 |
2007年 | 29篇 |
2006年 | 17篇 |
2005年 | 20篇 |
2004年 | 10篇 |
2003年 | 16篇 |
2002年 | 7篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1988年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有276条查询结果,搜索用时 15 毫秒
31.
32.
Isolation and culture of rabbit primordial germ cells 总被引:2,自引:0,他引:2
Kakegawa R Teramura T Takehara T Anzai M Mitani T Matsumoto K Saeki K Sagawa N Fukuda K Hosoi Y 《The Journal of reproduction and development》2008,54(5):352-357
Primordial germ cells (PGCs) are embryonic precursors of the gametes of adult animals and are considered stem cells of the germline. Since their proliferation in vitro correlates well with the schedule of developmental changes in vivo, they might be interesting research tools for genomic imprinting, germ-cell tumors and fertility. Furthermore, once primordial germ cells are separated and placed on a feeder layer with cytokines, they become cultured pluripotent cell lines called embryonic germ (EG) cells. EG cells share several important characteristics with embryonic stem (ES) cells as they can also contribute to the germ line of chimeras. To investigate the characteristics of PGCs and establish rabbit EG (rEG) cells, we cultured rabbit PGCs (rPGCs) in vitro with various combinations of leukemia inhibitory factor (LIF), basic fibroblast growth factor (bFGF) and forskolin on inactivated mouse embryonic fibroblast (MEF) feeder layers. The present study found PGC proliferation in early cultures and induction of rEG-like colonies. These cells expressed pluripotent markers, such as alkaline phosphatase activity, OCT-4, Sox-2 and SSEA-1, in the undifferentiated state; however, the cells did not develop into a teratoma when injected into the kidney capsules of SCID mice, although the restricted differentiation potentials to neural cells were determined via embryoid body formation. From these characteristics and further characterization of the germ stem cell markers Vasa, SCP-1 and SCP-3, we suggested that these were hybrid cells with characteristics somewhere between PGC and EG cells. 相似文献
33.
Ahimbisibwe John Bosco Inoue Kousuke Shibata Toshiyuki Aoki Takahiko 《Fisheries Science》2010,76(2):389-394
The effect of bleeding on white muscle quality in amberjack and red sea bream was evaluated by measuring ATP-related compounds,
volatile basic nitrogen (VBN), and the trimethylamine (TMA) content. The freshness was evaluated by the K value, and the degree of spoilage was elucidated by VBN and TMA. ATP was rapidly converted to ADP and AMP in the muscle and
IMP was the main product of ATP degradation during iced storage. For both species, the IMP content was higher in the muscles
of fish that were bled than in those unbled during iced storage. Conversely, the K value and the levels of hypoxanthine (Hx) and VBN were higher in the muscle tissue of unbled fish than in the bled tissue
of both species. Similarly, the TMA content was higher in the unbled muscle tissues of both species after a week of storage. 相似文献
34.
Satoshi Hashimoto Kenichi Ueno Kenichi Takahashi Toshiyuki Suzuki Yutaka Itabashi 《Fisheries Science》2010,76(3):529-536
Photosensitivity was observed in the mice used in bioassays of diarrhetic shellfish poisoning. The mice were intraperitoneally
injected with the extracts from the midgut glands of cultured scallops Patinopecten yessoensis gathered in early spring in Funka Bay, Hokkaido, Japan. The injections induced atypical symptoms in the mice within 24 h.
The symptoms included piloerection, substantial eye discharge, swelling of the ears and head, and ear scratching. They were
similar to those reported in studies of photosensitivity caused by pyropheophorbide in the midgut glands of abalones, which
are herbivorous gastropods. The problematic scallops also accumulated a large amount of pyropheophorbide-a. The amount determined with high-performance liquid chromatography was 300–530 μg per 1 g of the homogenate of the midgut
glands. The dose of pyropheophorbide sufficient to cause photosensitivity in a mouse is estimated to be 0.99–2.3 mg per mouse
with 20-g body weight. Moreover, comparative tests in mice showed that the onset of the symptoms required light and a substantial
amount of pyropheophorbide. Therefore, we determined that the observed symptoms were photosensitivity caused by pyropheophorbide.
Scallops, which are suspension-feeding bivalves, can accumulate a large amount of pyropheophorbide in the midgut glands depending
on the habitat environment. 相似文献
35.
Suzuki Toshiyuki Kamiyama Takashi Okumura Yutaka Ishihara Kenji Matsushima Ryoji Kaneniwa Masaki 《Fisheries Science》2009,75(4):1039-1048
Fatty-acid esters of dinophysistoxin-1 (DTX1) in scallops Patinopecten yessoensis, mussels Mytilus coruscus, and toxic dinoflagellate Dinophysis species, collected from Japanese seawater, were analyzed by liquid-chromatography mass spectrometry (LC–MS). Precursor ion
monitoring, multiple reaction monitoring for 18 fatty-acid esters of DTX1, and full-scan MS/MS spectra obtained with a hybrid
triple–quadrupole linear-ion-trap mass spectrometer showed that 14:0, 16:0, and 16:1 esters were the most abundant 7-O-acyl-DTX1 analogues in bivalves. Fatty-acids esters formed by conjugations at hydroxyl positions other than the 7-position
of DTX1 were not detected in the bivalves. DTX1 and okadaic acid-16:0 fatty-acid esters have been reported as the most abundant
ester in bivalves in several previous studies; however, we found that 7-O-16:1-DTX1 was the most abundant ester in some mussels in which 16:1 was more dominant than 16:0 in the free fatty-acid profile.
Comparison between 7-O-acyl-DTX1 and free fatty-acid profiles in the same bivalve samples suggests that polyunsaturated fatty acids are selectively
excluded in enzymatic acylation of DTX1. No 7-O-acyl-DTX1 was detected in any single-cell isolates of D. fortii, D. acuminata, D. mitra, D. norvegica, D. tripos, D. infundibulus, and D. rotundata. 相似文献
36.
37.
38.
Luiz L. Mafra Jr. Daiana Lopes Vanessa C. Bonilauri Hajime Uchida Toshiyuki Suzuki 《Marine drugs》2015,13(6):3920-3935
This study investigates the occurrence of diarrhetic shellfish toxins (DSTs) and their producing phytoplankton species in southern Brazil, as well as the potential for toxin accumulation in co-occurring mussels (Perna perna) and octopuses (Octopus vulgaris). During the spring in 2012 and 2013, cells of Dinophysis acuminata complex were always present, sometimes at relatively high abundances (max. 1143 cells L−1), likely the main source of okadaic acid (OA) in the plankton (max. 34 ng L−1). Dinophysis caudata occurred at lower cell densities in 2013 when the lipophilic toxins pectenotoxin-2 (PTX-2) and PTX-2 seco acid were detected in plankton and mussel samples. Here, we report for the first time the accumulation of DSTs in octopuses, probably linked to the consumption of contaminated bivalves. Perna perna mussels were consistently contaminated with different DSTs (max. 42 µg kg−1), and all octopuses analyzed (n = 5) accumulated OA in different organs/tissues: digestive glands (DGs) > arms > gills > kidneys > stomach + intestine. Additionally, similar concentrations of 7-O-palmytoyl OA and 7-O-palmytoly dinophysistoxin-1 (DTX-1) were frequently detected in the hepatopancreas of P. perna and DGs of O. vulgaris. Therefore, octopuses can be considered a potential vector of DSTs to both humans and top predators such as marine mammals. 相似文献
39.
Leila Basti Hajime Uchida Ryoji Matsushima Ryuichi Watanabe Toshiyuki Suzuki Toshifumi Yamatogi Satoshi Nagai 《Marine drugs》2015,13(12):7124-7137
The effects of temperature on growth and production of Lipophilic Toxins (LT) by a monoclonal culture of Dinophysis caudata was studied. The cell density of D. caudata increased significantly with increasing temperature, and was the highest under 27, 30, and 32.5 °C. Temperature affected the average specific growth rate (µ) during the exponential growth phase (EG), which increased from 15 °C to 30 °C, and then decreased at 32.5 °C. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed that this strain of D. caudata produced only pectenotoxin-2 (PTX-2) whose concentration increased significantly with incubation period, except at 32.5 °C. It was significantly different between temperatures ≤18 °C, ≥21 °C, and 32.5 °C. The cellular toxin production (CTP, pg·cell−1·day−1) showed variation with growth phase and temperature, except at 32.5 °C. The average net toxin production (Rtox) was not affected by temperature. During EG, the average specific toxin production rate (µtox) increased significantly with increase in temperature, reaching a peak of 0.66 ± 0.01 day−1 at 30 °C, and then decreased. Over the entire growth span, µtox was significantly correlated to µ, and this correlation was most significant at 27 and 30 °C. During EG, µtox was affected by both temperature and growth. This study shows that temperature affects growth and toxin production of this strain of D. caudata during EG. In addition, a positive correlation was found between toxin production and growth. 相似文献
40.
Imtiaj Hasan Shigeki Sugawara Yuki Fujii Yasuhiro Koide Daiki Terada Naoya Iimura Toshiyuki Fujiwara Keisuke G. Takahashi Nobuhiko Kojima Sultana Rajia Sarkar M. A. Kawsar Robert A. Kanaly Hideho Uchiyama Masahiro Hosono Yukiko Ogawa Hideaki Fujita Jiharu Hamako Taei Matsui Yasuhiro Ozeki 《Marine drugs》2015,13(12):7377-7389
MytiLec; a novel lectin isolated from the Mediterranean mussel (Mytilus galloprovincialis); shows strong binding affinity to globotriose (Gb3: Galα1-4Galβ1-4Glc). MytiLec revealed β-trefoil folding as also found in the ricin B-subunit type (R-type) lectin family, although the amino acid sequences were quite different. Classification of R-type lectin family members therefore needs to be based on conformation as well as on primary structure. MytiLec specifically killed Burkitt''s lymphoma Ramos cells, which express Gb3. Fluorescein-labeling assay revealed that MytiLec was incorporated inside the cells. MytiLec treatment of Ramos cells resulted in activation of both classical MAPK/ extracellular signal-regulated kinase and extracellular signal-regulated kinase (MEK-ERK) and stress-activated (p38 kinase and JNK) Mitogen-activated protein kinases (MAPK) pathways. In the cells, MytiLec treatment triggered expression of tumor necrosis factor (TNF)-α (a ligand of death receptor-dependent apoptosis) and activation of mitochondria-controlling caspase-9 (initiator caspase) and caspase-3 (activator caspase). Experiments using the specific MEK inhibitor U0126 showed that MytiLec-induced phosphorylation of the MEK-ERK pathway up-regulated expression of the cyclin-dependent kinase inhibitor p21, leading to cell cycle arrest and TNF-α production. Activation of caspase-3 by MytiLec appeared to be regulated by multiple different pathways. Our findings, taken together, indicate that the novel R-type lectin MytiLec initiates programmed cell death of Burkitt’s lymphoma cells through multiple pathways (MAPK cascade, death receptor signaling; caspase activation) based on interaction of the lectin with Gb3-containing glycosphingolipid-enriched microdomains on the cell surface. 相似文献